Is 4 a Prime Number?
2026-02-28 17:14 Diff
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Last updated on August 5, 2025

When a number is divisible by only 2 numbers that are 1 and itself, it is called a prime number. We use prime numbers in our daily life, like in Cybersecurity and ATM pins. Now Let us study what a prime number is and why 4 is not a prime number.

Is 4 a Prime Number?

Numbers are of 2 types, Prime and Composite numbers. 


4 is a composite number. We can check how 4 is a composite number using 4 different methods. Let us study what the methods are 

  • Divisor Counting Method
  • Divisibility Test
  • Prime Number Chart
  • Prime Factorization

Why Is 4 not a prime number?

A number needs to satisfy 2 criteria to be a prime:

  • It should have only 2 divisors. 1 and itself.

If it meets the above criteria, it can be considered as a prime number. Now, let us look at the different techniques to find if a number is prime or not.
 

Using the Counting Divisors Method

We will test if 4 is divisible by 2, 3, 5 or 7. If 4 is divisible by any of the numbers mentioned above, then 4 is not a prime no.

  • Since 4 is ending with an even number, we can say that 4 is divisible by 2.
  • Since the sum of the digits is 4, 4 is not divisible by 3 as 4 is not a multiple of 3. 
  • 4 is not ending with a 0 or 5. Therefore, it is not divisible by 5.
  • As 4 is a lower number than 7, it will not be divisible by 7.

We know 4 can be divided by one of the above-mentioned numbers, therefore it is not a prime number.
 

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Using A Prime Number Chart

Here, we will be using a chart that will contain all the prime numbers between 1 and 100. If the given number appears in the list, it is not a prime number. 

We can see that 4 does not appear here. So, it is not a prime number.
 

Using the Prime Factorization Method

Applying this method, we break the large numbers into small numbers to check the factors. This method is applicable only for composite numbers. 


The prime factors for 4 are 2 and 2. As the factors of 4 are more than 2, we can’t call 4 a prime number.
 

Common Mistakes to Avoid When Determining if 4 is a Prime Number

There are some special mistakes which the kids make while solving to see whether 4 is a prime number or not. Let us now look at some of these mistakes.
 

Important Glossaries for "Is 4 a Prime Number"

  • Factor-A number, if multiplied with another number gives us the required number.Example, 9x2=18, 9x3=27. In that, 2 and 3 are factors
  • Divisor- A number by which another number is divided is called divisor.
  • Composite number- If the number of factors for the given number is above 2, then that number is a composite number.
  • Multiple-The product we get while multiplying a number with another number.Example:- 9x2=18, 9x3=27. Here, 18 and 27 are multiple of 9.

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Hiralee Lalitkumar Makwana

About the Author

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.

Fun Fact

: She loves to read number jokes and games.